Telephone-call-distributing system.



A.H.,DYSON TELEPHONE CALL DISTRIBUTING SYSTEM.

APPLIQATION FILED JAN. 30. I9I3- RENEWED JAN. 22. I916.

Patented Mar. 19

SHEETS-SHEET I.

A. H. DYSON.

HELEPHOIIIE CALL DISTRIBUTING SYSTEM. APPLICATION- FILED 1AN.30, 1913.RENEWED JAN. 22. I916- 159A96u Patented; Mar. 19, 19m.

4 SHEETS-SHEET 2.

Z/ 2772795555: fizz/522232":

farm/557 v A. H. DYSON.

TELEPHONE CALL DISTRIBUTING SYSTEM. APPLICATION FILED JAN. 30, 1913.RENEWED JAN. 22'. 1916.

1,259,496. Patented. Mar. 19,1918.

asngfls snin 3. WW:- i m s 19 i b A. H. DYSON. TELEPHONE CALLDISTRIBUTING SYSTEM. APPLICATION FILED JAN. 30. 19:3. RENEWED JAN. 22.1916.

Patented Mar. 19, 1918.

In K3 fin/527E721 4 HEETS-SIEET 4. Y. L.

ALFRED H. DYSON, OF NEW .YOBK, N. Y., ASSIGNOR T0 KELLOGG SWITCHBOARDAND SUPPLY COMPANY. OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE-OALL-DISTBIBUTING SYSTEM.

Specification of Letters Patent.

Patented Mar. 19, 1918.

I hpplication'fllcd January 80, 1913, Serial No. 745,069. RenewedJanuary 22, 1916. Serial No. 78,761.

To all whom it ma concern:

Be it known tiiat I, ALFRED H. DYSON, a citizen of the United States ofAmerica, residing in New York city, county of New York, and State of NewYork, have invented certain new and useful Improvements in TelephoneCall Distributing Systems, of which the following is a specification.

My invention relates to telephone systems in general, certain featuresthereof being directed more particularly to telephone call distributingsystems, an object being to provide a system as named which is readilyapplicable to operating exchanges of a wellknown so-called three-wiretype.

Where it is desired to change over an operating manual telephone systemto a call distributing system 1t is apparent that it is a desirablefeature to be able to change over the existing system at the lowestexpense and at the same time secure a simple, positive and efficientlyoperative system, and to this end I have worked out my invention,several forms of which are shown in the accompanying drawings. The newfeatures of my lnvention will be more definitely pointed out in theensuing specification and claims.

Figure 1 comprising parts 1 and 2 illustrates one form of my invention.

Fig. 2 illustrates diagrammatically a contact bank and wiper arrangementof a preferred form of switch construct1on used with my invention.

Fig. 3 comprising parts 1 and 2 illustrates another embodiment of myinvention and Fig. 4 shows a cord circuit adapted for use with thesystem of Fig. 3.

Referring first to the system of Fig. 1 it comprises in general,substations A-connected by line conductors L to line circuits B whichterminate in jacks at a central oflice switchboard in a well-knownmanner. hach operators position includes answering plug C connected toan associated call distributing or cord selector switch D. Theseselectors D are divided into groups, each group having its bankterminals-multiply connected and extending to calling cord circuits Ewhich are also divided into groups and distributed among connectingoperators positions before which multiple terminals of the lines of theexchange are positioned. At the right end of Fig. 1, part 2 I haveillustrated what we will assume as a ters being used to indicate partscorrespondmg to the calling substatlon and-associated apparatus.

In general the system of Fig. 1 operates as follows: Assuming a callingsubscriber at A removes his receiver from its switch-hook to initiate acall, an associated line signal LS is operated before a distributinoperator who inserts an answering plug 0 into an an swering jack of thecalling line whereupon the associated distributing switch Dautomatically distributes the call to an idle connecting cord circuit Ebefore a connecting operator. The connecting operator in response to asi al 11 displayed at the seized connecting circuit E, ascertains bymeans of an operators telephone circuit, not shown, the number of theWanted substation. The connecting operator then inserts the plug F ofsaid connecting cord circuit into a jack of the wanted line-and thenapplies ringing current to the terminals thereof.

After the subscribers have finished conversation they replace theirreceivers upon their respective switch-hooks whereby a disconnect signalis received at the cord circuit E and the connecting operator thereuponWithdraws the connecting plug F from the jack of the called line,causing the display of a disconnect signal DS at the plug C whereuponthe distributing operator withdraws the associated plug C from the jackof the calling line.

, Before proceeding with a more detailed description of Fig. 1, I willrefer to the selector mechanism of the distributing switch D, preferablyemployed.

For use with the selector and connector circuits of the system of Figs.1 and 2, a switch such as is shown in an application of William Kaislingfor automatic switch for telephone systems, Serial No. 600,664, PatentNo. 1,131,140 filed'January 3rd, 1911, may be used.

The switch referred to in the previous paragraph, in general comprises abank of contact made up of 100 sets of contacts with three contacts 5,6, 7, to each set, and divided into ten groups of ten contact sets eachas illustrated diagrammatically in Fig. 2. A set of wipers T, P, S, areprovided, to cooperate with the bank contacts, a primary magnet(corresponding to PM of the switch circuits) being adapted to primarilyadjust,

the wipers through the medium of a primary shaft PS to select a groupofcontacts, and a secondary magnet corresponding to SM of theswitchcircuits is provide .-to step the wipers throu h t emedium of asecondary shaft SS in a secondary direction in a plane at right anglesto the primary, to select a contact set of the selected group.

' The switch construction is such that the I Wiper wiper are advancedagainst the tension of a pair of so-called watc opposing each movementrespectively.

For each row or group of contacts 5, 6, 7

a grou them to control, the secondary magnet is. again actuated to stepthe wipers in a sec-1 ondary direction beyond the last contact of thegroup whereby they are automatically restored to normal by the springsreferred to, but over a different path than thattaken by the wipersinthe advance movement of the switch in selecting a contact, such a.

complete travel of the wipers being indicated .by the dotted line inFig. 2. Thus, in

the operation of the switch the contacting ends of the wipers travel ina primary direction to select a group of contacts, then in a secondarydirection to select a contact in the group, and in the release of thewipers this secondary travel is continued until the contacting ends havepassed beyond the last .contact in the group, whereby they areautomatically released to continue their restoration to normal, thiscontinued movement being in a plane parallel to the primary movement butin an opposite direction until they I reach a point directly above thestarting point when they are moved" downward through a plane parallel tothe secondary movement, but in a direction opposite to the secondarymovement, until they reach their normal starting point.

A set of primary off-normal spring contacts PON are moved upon the firstprimary step of the switchwhile a set of secondary ofl-normal springcontacts SON are moved upon the first secondary step of the switch.

If the primar adjustment of the switch is continued until the wipershave passed beyond the last contact/8 and row 5, 6, 7, a primaryover-run switch POR is closed while ifthe secondary adjustment of thewipers T, P, S, is continued until they pass beyond a row, a secondaryover-run switch SOB is closed, these over-run switches being restored inamanner as will be apparent springs, one spring frelay CO, answering andcalling that for a more complete understanding of this switch, referenceis to vbe had to the i from the drawing. It is to bei'unde'rstoodcomprises a substation A, the one illustrated .bein of'a well-knowntype, connected by a line comprising conductors 1 and 2 to a linecircuit B at a central oflice. Said circuit B comprises a line relay LB,9. cut-01f jacks J multiply connected tothe lin'e conductors 1', 2-, anda line signal LS.

A plurality of answering plugs C are provided at each distributingoperators position, each one being connected by talking conductors 3, 4,to a distributing switch D.

A third conductor of plug C is connected to a starting relay STR whichrelay energizes upon inserting plug C, to start the selecting operationof the associated distributing switch D. p j

- As already outlined the distributing switch D has its bank terminalsarranged in groups, and the wipers are adapted to be moved to select agroup having an idle set of terminals and thereafter to such an idle setof terminals in the selected group. Each set ;of such terminalscomprisesa testterminal '5, a' primary talking terminal 6 and asecondary talking terminal 7 there being preferably 10 such sets in eachrow as already outlined. For each such row of terminals a group terminal8 is provided, andthere being 10 rows of terminals 5, 6, 7, there are ofcourse 10 group terminals 8 and a cooperating group ,wiper GT; A testwiper T is provided for the terminals 5, and primary and secondarywipers P and S for the terminals 6 and 7 respectively. The primaryadjustment of the wipers in selecting a group is efiected by a primarymagnet PM, while the secondary adjustment of the wipers to select acontact of a group is eifected by a secondary magnet SM. A primary relayPR controls the primary adjustment bf the switch, while a secondaryrelay SR controls the secondary adjustment of the switch.

Each switch D also has a release relay RR, and a talking circuit closingrelay CL, said relay CL being energized after an idle cord circuit E isselected.

The off-normal and over-run switches are indicated by referencecharacters which will be clearly understood from the switch descriptionalready 'ven. The over-run switches .in conjunction with the over-runrelay ORR are adapted to automatically restore switch D to normal,should all of the cord circuits to which it has access be busy. Forinstance should all of the cord circuits be bu ya the a s swf ch D isstarted,

iao

new, i

the up wiper GT will of course step beyon the last group contact 8 andat this point switch POR is moved to its alternate position causing theenergization of relay ORR and thereby effecting the restoration of theswitch. Should some of the cord circuits to which a started switch D hasaccess be idle, group ,wiper GT would of course stop upon selecting thefirst group containing such an idle cord, but should all of the cords inthis selected group of contacts be rendered busy before the test wiper'1 reaches them, the secondary adjustment of the switch is continueduntil wipers T, P, S, are advanced beyond the last contact in the groupwhereupon'secondary over-run switch SOR is moved to its alternateposition to effect the energization of ORR and the restoration of switchD. 1

As already outlined each row of switch contacts has preferably 10 setsof contacts 5, 6, 7 and there is a group contact 8 provided for eachrow. Therefore, means are provided to render a set of multiply connectedgroup contacts 8 busy while the associated 10 cord circuits E are busy.To this end a group busy relay GB is provided for each cord circuit,said relay being energized as soon as its cord circuit is selected.

A series busy circuit 9 extends in series through normally open contacts10 of each group of ten relays GB, the last relay GB? of the set havingits contact as 10 connected to ground so that as long as the ten relaysGB are energized this ground connection from alternate contact 10 ismaintained connected to its associated group contacts 8. It will beapparent that as long as any one or more of a group of relays GB aredeenergized, this series circuit will be interrupted so that theassociated group contacts 8 remain selectable.

Referring now to cord circuit E, it comprises a repeating coil RCconnected in cir-. cuit with the talking conductors ofthe cord circuit,and a calling plug F. An answering supervisory relay AS- is adapted tobe energized upon selection of its cord circuit to light the callingsignal 11. A calling supervisory relay CS is also provided whichcontrols a supervisory signal 12. A shimt relay SH is energized uponinserting plug F in. a called line, to efiace signal lamp 11 while theringing relay BI is adapted to apply ringing current to the terminals ofthe called line.

A ringing key N is provided for each cord circuit E said key beingadapted to ring four party-line substations selectively or a singleline-substation. Five ringing contact sets 0, M, K, H and-G areconnected to generators 13, 14, 15, by connections extending through theinterrupters 16, 17, and 18. Generator 13 is adapted to provide positivepulsations, generator 14 negative pulsations, and generator 15 asuitable alternating ringing current. The interrupters 16, 17 18, areconstantly rotating and alternately connect the associated generator andbatteryb-to the conductors 19, 20, 21. The ringing key N is so connectedthat when contacts 0 are operated, alternating current generator 15 isconnected in bridge of the tip and ringacontacts of plug F. When contactsets are operated negative pulsations from generator 14 are connected tothe tip of plug F. Contacts K are adapted for connecting positivepulsations from generator 13 to the tip of the plug, contacts H areadapted to connect positive pulsations from generator 13 to the ring ofthe plug and contacts G when operated connect negative pulsations fromgenerator 14 to thering of the plug. The five sprin contacts areindicated by signs which rea ily show the current which is adapted to beconnected and whether to the tip or sleeve side all of which will beapparent from the foregoing description. Key N is so arranged that whenany of its plungers are actuated it will be held in its actuatedposition by clutch magnet CM until said magnet is deenergized. A ringingdisconnect relay DR is connected in the ringing circuit and is adaptedto be energized upon response of the called subscriber to eflect theenergize.-

tion of clutch magnet control relay RR and thereby release clutch magnetCM and ringing relay RI.

In connection with called line L I have shown a substation A having acall bell is which is connected to the tip side of the line and adaptedto be operated by positive pulsations when key K is pressed. In a likemanner bells h, m, and g, are adapted to be operated when theircorresponding keys H, M or G are depressed. It will be noted that likereference characters indicate the corresponding keys and substations.

Operation.

Having described in general the apparatus of Fig. 1, the operation ofthe system will now be described. Assumin the subscriber at substation Aremoves his receiver to initiate a call, a circuit for line relay LR isestablished over the calling line, thereby energizing said relay andlighting the line signal LS. The distributin operator before whom theanswering j ac of substation A terminates, in response to said signal,in-

serts a plug G into the answering jack J of the calling line therebyconnecting the talking contacts of plug -0 with the talkin contacts ofjack J, while starting relay ST is connected through the third conductorin' series with cut-oil relay CO thereby energizing both relays STR andCO. Relay STR therefore closes its alternate contact 22 establishing acircuit for primary relay 3 PR traced from while wipers; T, P, S,

cup of bank contacts 5, 6, 7.

- Assuming justment of switch D.

. energization of P, S, into connection with alternate contact 25, establshin of contacts leads to a its test contact 5 w1ll\have aground or'ground atsaid' contact 22, normal contact-23 normal contact 24 and thewin of 1 3 to battery.- Said relay PR there ore is ener ed closing itsan 0 erating circuit for primary magnet I M. aid magnet thereforeattracts its armature and causes a primary step'of the switch wiperswhereby group-test wig-er GT is moved mto connection with the.

are moved opposite the first row or all 0 the cord circuits extendingfrom this first group of bank contacts" are busy, all of their relaysGBare energized and therefore the first group contact 8 has a gound orbusy potential connected thereto as is indicated diagrammatically thedrawing. Therefore, primary relay PR is maintainedenergized overa-circuittraced from said grounded contact 8, alternate contact 26, thewinding of PR to battery. Therefore magnet PM causes another primarystep of the switch and assuming the second group of bankcontacts arebusy' a third primary step of the switch is effected. Assuming there isan idle cord circuit in this third group, there will be no busypotential upon its group contact8 and therefore relay PR deenergizesinterrupting its alternate contact 25 and preventing any further primaryad- Thus it will be seen that switch D has automatically selected thefirst group of bank contacts havingan idle cord circuit.

The next step is to cord of this selected group this being brought aboutas follows. Upon said de- PR, its normal contact 25 closes establishinga circuit for secondary relay SR traced from-said ground at normalcontact 25, alternate contact 27, normal contact 28, winding of SR tobattery. Relay Slttherefore energizes closing its alternate contact 29establishing an operating circuit for secondary magnet SM which attractsits armature and advances wipers T, the first set of contacts 5, 6, 7.Assuming this first set busy cord circuit,

busy potential connectedethereto, (due to its relay GB, contact 40 beingclosed) and therefore a locking circuit for SR is established from saidgrounded test contact 5, test wiper T, alternate contact 30, normalcontact 31, the winding of SR to battery. It will be noted that upon.the first secondary ste rugted so that the initial circuit for SR isopen. Relay SR remaining energized, magnet SM advances the wipersanother secondary step and in fact continues to do so as long as testwiper T is engaging busy test contacts 5. Upon reaching the conducnotedthat during this seco st group contact 8 SR to prevent the ground selectthe first idle of the switch SON contact 28 is inter-- assume is thefirst idle one. of the group,

there being no busy contact 5 the circuit'for SR is interrupted,deenergizing said relay to interrupt the circuit for SM and prevent anyondary adjustment of switc D.

dary travel of S has'its circontact 32 0f the switch, secondary wip rcult interrupted atmormal "tact 33 of RRinterfermg with anyexistingconnections with which wiper'S may engage.

"SwitchD has now selected the first idle cord of the selected groupandthe next step is to signal the operator at the selected connectingcord circuit E. Upon said deener gization of relay SR, a circuit foranswering supervisory relay AS is established traced from ground atnormal normal contact 32, conductor 34, normal contact 35, wiper S andcontact 7, secondary conductor 36, the winding of AS and noninductiveresistance 37 in multiple, through a winding of repeating coil BC tobattery. Relay AS is therefore energized closing its alternate contact38 and establishing a circuit for signal 11 traced from battery throughsaid signal 11, alternate contact 38,

busy relay GB to ground, this series circuit contact 33 of RR,

potential upon its test:

1o; further sec- It will be om normal concausing the illumination oflamp 11 and the v I energization ofrelay GB. Relay GB theref fore closesits alternate ing ground to the particular cord circuitE busy andnonselectable.

contact 40 connect- Alternate contact 10 of GB is test contact 5 andrendering also closed, thereby affecting a step in the closure of theseries conductor 9, so that when all of the relays GB, GB, etc., in theseries are energized, ground will be con-' nected to the associatedgroup contact 8 to render it busy. Of course as long as any relay GB ofa series is at normal, this series conductor 9 is interrupted allowingits group to be selecte Referring again todistributer switch D, upon theconnecting of the ground or busy potential to the connected testterminal 5,

a circuit for closing relay CL is established traced from said groundedcontact 5, wiper T, normal contact 30,- conductor '60 and the winding ofCL to battery. Relay CL therefore energizes closing its alternatecontacts 61, 62, and establishing the continuity of the talkingconductors of switch D. Although the initial circuit for relay AS ofcord circuit E is interrupted when normal contact 35 of CL is opened,said relay AS is maintained energized by the alternate path traced overthe heavily marked conductors including the calling line andback overthe ti or primary talking conductor 62 and a wind:

ing of repeating c il RC g und. Thus a ane ielay is now under thecontrol of the I for release relay BR traced from batterythrough winding65 of RR, alternate contact .64, conductor 66, alternate contact 27 andnormal contact-25 to ground. Relay ER is, therefore energized closingits lock- 110 ing contact 67 and thereby establishing a locking circuitto the said grounded normal contact 25. Alternate contact'23 of RR isalso closed thereby connecting Winding 68 of BE in circuit with thegrounded alternate contact 22 which establishes another energizingcircuit for ER and prevents itsrestoration until plug C is withdrawnfrom its jack.

t The connecting operator in response to said signal 11 connects hertelephone circuit (not shownlto ascertain-the wants of the callingsubscriber and finding that connection is desired with substation Ainserts the plug F of the selected cord circuit E into 25 a jack J ofthe Wanted line and thereafter depresses the plunger which actuates keycontacts Upon connecting plug F to 'jack J a series circuit includinshunt relay SH, supervisory lamp 12 an cut-ofi' relay CO is establishedcausing the energization of relays SH and CO and the illumination oflamp 12. This circuit may be traced from ground through the winding ofCO third contacts of jack and plug, lamp 3 12 and the winding of SH tobattery. Re-

. lay CO is thus energized to remove the substation control of itslinerelay-LR. The energization of shunt relay. SH establishes a shuntcircuit around the signal 11 causing 40 its efi'acement, this shuntcircuit being established from-said lamp 11 alternate'contact 38,alternate contact 39, which is now closed, resistance 41 to batterywhile the original circuit through lamp 11 is interrupted at normalcontact 39 and replaced through alternate contact 42. Thus enough"current is diverted through resistance 41 to cause the efiacement ofsaid signal 11. Also,

- responsive to energization of SH, its altervnate contact 43 is closedestablishing a circuit through normal contact 44 and the windings ofelectro-magnets CM and RI to battery causing their e'nergization. Theenergization of. clutch magnet CM is effective 5 to hold the operatedkey Kin its ringing position while the en'ergization of ringing relay RIcloses alternate contacts 45, 46, to connect ringing conductors 47, 48in circuit with the terminals of the called line. The

operator having actuated key K, a circuitj for call bell k isestablished traced from pul-'.

sating generator 13, through interrupter 16,

conductor 19, alternate contact 49,,winding 50 of disconnect relay DR,upper normal 6 contacts of keys H and G to conductor 47,

alternate contact 45, tip of plug F, jack J through the condenser andcall bell is of substation A to ground. Due to the operation ofinterrupter wheel 16, ringing pulsations and battery are alternatelyconnected 7c in circuit with the called line but due to interpositionofthe condenser at the called substation no battery flow is permitted.

Upon the'removal of the receiver at A,

in response to the call, a path for direct current is established atsubstation A and therefore as soon as the battery segment of interrupter16 is connected in circuit with the called line a flow of currentthrough winding 50 of disconnect relay DR is established, tracedfronibattery through said in: terrupter 1-6 to conductor 19, and. thenover the previously described path vi or ringing current to substation Areturning over conductor Z ring contacts of jack and' plug, alternatecontact 46, conductor 48 and alternate contact 150 of key K to ground.This flow of direct current causes the energization of disconnect relayDR whereby its normal contact 51 isinterrupted, opening the direct; 9o.shunt around the Winding ofrelay (1BR permitting the energizationthereof whereby its normal contact 44 is interrupted, causing therestoration of ringin relayrRT-and clutch magnet CM. Relay 'Q RRallso'lopens its'contact 1552 upon its energizatiomtlilreby I preventinga denergization of tlie'i relay when disconnect relay DR subsequently restores following therestoration of' Rlr" The two sub-stations A and Aarejnow connected by a. conversational circuit which is indicated by theheavily marked conductors and due to the supervisory relay CS beingincluded in the circuit of the called line, upon the said removal of thereceiver at substation A this relay CS is energized closing itsalternate contact 52 and thereby connecting resistance 53 in shunt oflamp 12 to'cause its efiacement.

Disconnection.

After the subscribers have finished conversation they will replace theirreceivers upon their respective switch-hooks, thereby causing theillumination of signals 11, 12 of cord circuit E, this being awell-knowndisconnect signal. The replacing of the receiver at substation A ofcourse restores calling supervisory relay CS whereby its cuit whichincluded shunt relay. SH, signal 12 and cut-off relay CO Relay C0 ofcourse restores thereby restoring the substation control to its'linerelay LE while the restoration of SH interrupts the circuit for relay GBat alternate contact 42, and by the interruption of said contact 42interrupts the circuit for signal 11 causing its effacement. Upondeenergization of relay GB, its alternate contact 10 is interrupted,rendering the associated group contact 8 selectable so far as the ordcircuit E is concerned. The interruption of alternate contact 40 of GBcauses the interruption of the circuit of closing relay CL whereby saidrelay restores interrupting the circuit through the heavily markedtalking conductors at switch D.

At this time relay BB is still energized with its normal contact 33interrupted so that a reoperation of relay AS of the connected cordcircuit is prevented. The closing of normal contact 69 of relay CL esyno tablishes. a circuit for disconnect signal -DS while the closing -ofnormal contact 64 of CL establishes a release circuit for relay SR thiscircuit being traced from battery through the winding of SR, alternatecontact 31 of RR, normal contact 64, conductor 66, alternate contact 27,and normal contact 25 to ground. Relay SR, therefore energizes closingits alternate contact 29 whereby magnet SM advances the wipers in asecondary direction beyond the last contact of the row whereby they areautomatically restored by spring tension as previously described inconnection with the switch structure.

Upon restoration of PON, its alternate contact 27 is opened therebyinterrupting the circuit for SE to cause its deenergization andrendering magnet SM inert. The interruption of this alternate contact 27interrupts through winding 65 of relay RR but said relay is maintainedenergized through its other winding 68 and alternate contact 22 of STHuntil plug C is withdrawn, this energization of RR preventing anotherselecting operation of switch D until another call is answered. Uponwithdrawal of plug C the series circuit including relays CO and STR isinterrupted causlng the restoration of these relays,'the restoration ofSTE interruptin the locking circuit through winding 68 of R allowing itto restore. Switch D being at normal is now available for use inextending other connections.

' Over-mm switches.

I Assuming now that at the time the dis-" tributmg operator insertedjack J of the calling line,

plug G into .a all of the cord circuits to which it has access are busy,relay .STR is of course energized followed by the energization of'PR asbefore and the the locking circuitprimary adjustment of the switch coilfurther locking circuit for relay PR, it restores to normal interruptingthe circuit for PM and by theclosing of its normal contact 25establishes a circuit for SR as previously traced. Relay SR thereforeenergizes and closes a circuit through SM whereby the wipers receive asingle secondary step which causes switch SON to interrupt its normalcontact 28 and there being no locking circuit for relay SR (as testwiper T is not engaging a contact) said relay SR restores interruptingthe circuit for SM. Thus the wipers are left off-normal and should berestored. To this end I provide the overrun switches and over-run relayORR. The switch D having stepped beyond the last group of contacts inits primary adjustment, primary over-run switch, POR has been moved toits alternate position. Therefore when relay SR restores as referred toa circuit for ORR is established traced from ground at normal contact 33of RR, normal contact 32, alternate contact 71, and the winding of ORRto battery causing its energization; Its alternate contact 72 istherefore closed establishing a circuit for CL traced from said groundedcontact 72, alternate contact 73, conductor 74, conductor 60, and thewinding of CL to battery. Relay CL therefore energizes closing itsalternate contact 64 and establishing an. energizing circuit throughwinding 65 of relay RR over the previously described path'to ground atnormal contact 25. RR therefore energizes closing its alternate contacts67 and 23 thereby locking relay in its energized condition as beforedescribed. Normal contact 33 of RR is therefore interrupted interruptingthe circuit for ORR and causing its restoration whereby itsw alternatecontact 72 is interrupted allowing restoration of CL. Normal contact 69of CL is therefore closed and a circuit for disconnect signal DS isestablished over a the previously described path from the alternategrounded contact 33. The closing of normal contact 64 of CL upon itssaid denergization establishes a release circuit for SR over thepreviously described path which may be traced from battery through thewinding of SR, alternate contact 31, normal contact '64, alternatecontact 27 and normal contact 25 to ground. Relay SR therefore closes awhen all of the cord circuits to which a switch D has access are busywhen the op- 20 multiples is seized by another distributer "greater thantwo-secon s.

erator inserts plug C in a jack,- lamp DS is 'lightedw'ithin acomparatively short time,

, course it is applicants intention to provide sufficient apparatus totake care of the incoming calls in a suitable manner.

Should switch D receive its primary adjustment to select a row ofcontacts having an idle contact set, and then before the wipers reachsuch an idle contact set (which we will assume-is the only one in theselected row)- said contact set or rather one of its switch D, over-runswitch SOR is brought into play. In such case all of the contact sets ofthe selected row being busy, the wipers would be stepped beyond the lastcontact of the row due to the fact that the locking circuit forsecondary relay SR is maintained closed through the busy test contact 5.Upon the switch reachingthisover-run point, contacts SOR are closed, sothat when relay SR deenergi'zes, circuit for over-run relay ORR isclosed traced from battery through the winding of said relay, alternatecontact 171,'normal contact 32 to ground at normal contact 33. Relay ORRtherefore closes its alternate contact 72 establishing an energizingcircuit for relay CL traced from said grounded contact 72,

alternate contact 173, conductor 60 and the winding of CL to battery.Relay CL, therefore closes its alternate contact 64 and establishes anenergizing circuit for the winding 65 of relay RR traced from battery tosaid winding 65, line contact 64, conductor 66, alternate contact 27 toground at normal contact 25. RelayRR therefore energizes closing itslocking contact 67 and also connecting its locking circuit 68 throughalternate contact 23 to ground at alternate con: tact 22. As soonasrelay RR energizes it interrupts its normal contact 33 therebyinterrupting the circuit for ORR which restores and due to theinterruption of its alternate contact 72, causes-restoration of relayCL. Relay CL being at normal and relay RR being still energized, acircuit for disconnect signal DS is established over the previouslydescribed path which includes normal contact 69 and alternate contact33, and the operator observing this signal lmows that the associateddistributing switch D has failed to pick up an idle cord. The switch Dhaving of course restored to normal cannot be operated again until plug0 is withdrawn from the jack to cause deenergization of relay STRand'thereby the restoration of release relay RR. The operator havingobserved the signal DS as already referred to may withdraw .plug 0 fromthe, jack' and immediately insert it again to try switch D once more, orshe may use another plug 0 and associated distributing switch"D. v

' Fig. 3.

In Fig. 3, I have illustrated another embodiment of my invention, theconnecting operation of the system shown therein differing in somerespects from that of Fig. 1. In the system of Fig. 3, no distributingoperator is required but a calling line has its circuit automaticallyextended-t0 a distributing switch D which switch extends the calllngline circuit to an idle cord circuit E In place of aplug C, a lineselector LS is paired with each'cord selector B such an idle pair ofswitches LS and I) being selected and started through the medium of 'amaster switch MS which is com mon to a group of lines and pairedswitches LS and D The present system is also readily applicable toinstallations having line clrcuits as B and cord circuits somewhatsimilar to E of Fig. 1, and in the present figure, that is Fig. 3, Ihave indicated the apparatus which corresponds to apparatus of Fig. 1,by like reference characters except for the suflix which has been addedto the reference characters. In this way I believe the operation andsimilarity more readily apparent.

In applying the present system to installations having line circults asB of Fig. 1, the answering jacks, and line signals as LS may be removedand an additional contact 101 provided for the line relay. As I preferto use 100 point selector switches LS I divide the lines into groups of100 and for each such group of 100 lines, 10 line selector's LS areprovided. The same switch construction asdescribed in connection withFig. 2 is used for the line selector LS except that four contacts 102,103, 104, 105, are

provided for each line circuit, and wipers P S T}, and W respectivelyare provided for cooperating with said contacts. Each group of 100 linesis then multiply connected to the contact sets of the associated tenline selectors LS. The lines are then dividedinto minor groups of 10lines each, thesebeing preferably the 10 lines connected to each row of10 contact sets and for each such minor group a group relay GR isprovided being connected to the alternate contact 101 of the associated10 line relays LR so that each relay GR may be energized upon initiationof a call over any of its associated 10 lines. Each group relay GR thenhas its grounded normal contact of the two figures will be.

106 connected to the corresponding group contact 107 so that when thegroup relay GR is energized it removes ground from the multiplyconnected contacts 107 of the 10 associated line selectors torender themselectable when energized by group test wiper GT The normal contact 101of each line relay is connected to the corresponding line test contacts104 of the 10 line selectors so that the started line selector will stopin its secondary adjustment when its test wiper T reaches the ungroundedtest contact 10% of the calling line. Wiper W and the associated contact105. are provided whereby an energizing path for the cut-off relay COmay be established when the calling line is seized, and also foroperation of certain relays of the switches LS and D Master MS.

For each oup of 10 paired line and cord selectors LS and 1)respectively,- a master switch MS is provided, having wipers 108, 109with a simple rotary motion and adapted to connect with a plurality ofsets of con-- tacts 110, 111, said contact sets being equal in number tothe number of associated paired selectors, which number is preferably10, although more or less may be used, according to the traffic. A motormagnet MM and driving mechanism is provided for advancing the wipers108, 109, in a step by step movement over the contacts 110, 111. Anofl-normal'contact ON is provided which is adapted to be closed upon thewipers leaving their normalposition, and an over-run contact OR isadapted to be closed upon the wipers stepping beyond the last or tenthcontact of the set. A release magnet RM is also provided which isadapted to be energized when the wipers have stepped beyond the lastcontact of the row due to the closing of over-run contact OR, whereby aretaining pawl is withdrawn and the wipers '108, 109 restore to normalby spring tei1 sion where they engage the first set of contacts. SwitchMS is preferably arranged to have its wipers 108, 109resting uponcontacts leading to an idle pair of switches so that upon initiation ofa call, such a pair of idle switches is started, switch. LS to selectthe calling line and switch D to select the first idle cord circuit EThis starting circuit for the selector switches-is controlled throughthe normal contacts 112 of magnet RM, said contacts being connected'overcommon conductor 212 to the alternate contacts 113 of the 100 linerelays LR of the group. As soon as the calling line has been connectedthrough the medium of a pair of switches LS and D to a cord circuit Ethe master switch advancing relay AB is energized and closes a circuitfor motor magnet hm whereby the wipers are advanced and relay ARmaintained energized until an idle set ofcontactsiill, 111, are ea"gagd- J a Operation of 3.

ing line. Relay LE also closes alternate contact 101 to cause theenergization ofits group relay GR whereby normal contact 106 isinterrupted to remove ground from the group test-contacts 107corresponding to the 5 roup of 10 contact sets or line terminals withwhich the calling line. is connected. Also upon energization ofLIE-alternate contact 113 is closed establishing a starting circuit forthe idle pair of selectors LS and D with which the wipers of masterswitch MS is then connected. This starting circuit is traced from groundat alternate contact 113, common conductor 212, normal contacts 112,114, wiper 109 and the engaged contact 111, conductor 115, to connectingpoint 116, the starting circuit dividing at this point and including theprimary relays PR ,'PR of switches LS and DE. The circuit vfor PR istraced from said point 116, conductor 117,

normal contact 118 and the winding PR to battery causing theenergization thereof and establishing an operating circuit for theprimary magnet PM from alternate contact 119. Magn et PM thereby.advances the Wipers a single primary step whereby group wiper GrTengages the first group contact 107. Assuming there is no line seekingconnection in either the first or second minor groups, the first twocontacts 107 will be grounded through the connected 'group'relays GR sothat a locking circuit for primary relay PR is established from saidgrounded contact 107, wiper GT alternate contact'120 and the winding ofPR to battery. Relay PR gized grounded contacts 107' so that magnet PMcontinues the primary adjustment ,of'the wipers until the ungroundedcontact 107 is 01 course remains eneras long as wlper GT is engagingreached whereupon relay PR retracts its armature interrupting thecircuit for magnet PM Wipers P S T W, have now 7 been advanced to apoint opposite the third group of contacts 102, 103, 104:, 105, which isthe sub-group containing the terminals of the calling line. Thesecondary adjustment ofswitch S is now efiected, this occurringresponsive to the deenergization of PR. Upon saiddenergizatio'n of PR acircuit for secondary relay SR is established traced from groundat'normal contact 119 of PR,

alternate contact 121, normal contact SON,

naaaaec A and the winding of SR to battery. Relay SR therefore closesits alternate contact 123 establishing an energizing circuit forsecondary magnet SM whereby wipers P S T, W, receive a single secondarystep advancing them into engagement with the first set of line contacts.Assuming the line of substation A is the first line of this groupseeking a connection, it will be the first line having its terminal 104.ungrounded so that upon wiper T engaging the first contact 104 of therow or group, due to the ground con nected thereto, a locking circuitfor relay SR is established through alternate contact 124 so that magnetSM advances the wipers another secondary step and in fact continues thissecondary adjustment until wiper T engages the test contact 104 of thecalling line. Upon reaching this contact the circuit for SR isinterrupted causing its deenergization whereby the circuit for SM isinterrupted and the switch. wipers rendered inert, and in engagementwith the terminals of the calling line. Thus, it will be seen how acalling line is selected by the line selector.

We will now take up the operation of the cord selector D Returning tothe starting circuit and to point 116, the ground connec-. tion overconductor 115 is extended toward the right over conductor 126. normalcontact 127, and the winding of PR to battery causing the energizationof relay PR whereby its alternate contact 128 is closed establishing anoperating circuit for primary magnet, PM Magnet PM upon its firstenergization advances the wipers of switch D a single primary stepwhereby group test wiper GT engages the first group contact 8 which wewill assume has a ground or busy potential thereon due to the busycondition of the associated cord. circuits E Therefore a locking circuitfor PR is established from said grounded contact 8 through alternatecontact 129, and the winding of PR tobattery so that magnet PM advancesthe wipers another step and in fact continues this primary adjustment aslong as wiper GT is engaging busy contacts 8 Upon reaching the thirdcontact 8 which we "will assume has an idle cord circuit in itsassociated sub-group, circuit for PR is interrupted causing thedeenergization thereof, and the interruption of the op crating circuitfor PM whereby anyjfurther primary adjustment of the switch D isprevented. Thus by the primary adjustment of switch I), a sub-group ofcord circuits with an idle circuit having been selected, a secondaryadjustment of the switch is brought about to select such an idle cordcircuit in this selected sub-group. lherefore upon deenergization of PRits normal contact 128 is'closed establishing a circuit for secondaryrelay SR traced from grounded normal contact. 128, alternate contact130,

contact SON and the winding of SR? to battery. Secondary relay SR istherefore energized closing its alternate contact 131 and establishingan operating circuit for secondary magnet SM whereby wipers P, T", S areadvanced a single secondary step to engage the first set of contacts 5 67 Assuming this first set of contacts leads to a busy cord circuit E thetest contact 5 thereof has a ground or busy potential connected theretoso that a locking circuit for SR is established traced from thisgrounded contact 5 wiper T alternate contact 132, normal contact 133,and the windin of SR to'battery. Upon this first secon ary step of Dcontact SON is interrupted just before wiper T connects with contact 5to prevent shunting the cut-01$ relay of a call ing line connectedtherewith, by the ground from normal contact 128. Therefore, thissecondary adjustment of the switch is continued until wiper T reaches anungrounded or idle test contact 5 which we will assume is the oneleading to the cord circuit E shown. Relay SR therefore loses itsenergizing circuit and interrupts the circuit for 8M rendering thewipers inert.

lhus the calling line having been selected and an idle cord circuit Ehaving been selected, the connection will be completed by closing relayGL and the line signal 11 operated. This is brought about upon thedeenergizationof SR by a circuit for answering supervisory relay A8 and37 in multiple, conductor '36 contact 7 wiper S normal contacts 134,135, 136, to ground whereby relay A5 is energized closing a seriescircuit including lamp 11 group busy relay GB closing relay GL andcutoil relay CO this circuit being traced from battery at E through lamp11 alternate contact 138, relay GB, conductor 139, contact 5 and Wiper Tnormal contacts 132, 140, winding of CO to ground. These three relays COGL and GB, are energized and signal 11 is illuminated to indicate thecall to the operator. The energize.- tion of GB eltects a step in theclosing or the series circuit 9 toward rendering the corresponding groupcontacts 5 busy in a manner as already. explained. The energization ofCO causes the interruption of the circuit for line relay'LR therebyclosing normal contact 101 to render the associated test contact 104unselectable, while the interruption of alternate contact 101 restoresgroup relay GR, (providing no other line in the group of 10 is calling.)to restore the associated group contact 107 to a grounded ornon-selectable condition. The interruption of alternate contact 113 ofLB removes ground Jtrom the starting conductor 212 and nor ire malcontact 112 until some other line in the group of 100.is calling. Itwill alsobe noted that due to the connection of battery to enof relay GLcloses alternate contacts 141 and 142, thereby extending the talkingcircuit of the calling line to the selected cord circuit E wherebysupervisory relay AS is included in circuit with the calling line andmaintained energized by current flowing over the heavily markedconductors. Also upon energization of GL release relays BB and BB areenergized, the circuit for BB being traced from battery through thewind- .ing thereof, alternate contacts 143, 121 to ground at normalcontact 119 causing the energization of BB whereby its alternate contact144 circuit for itself so that it will remain energized until the switchis restored and FUN restored. The circuit for BB is traced from 1battery through the winding thereof, alternate contact 145, 130 toground at normal contact 128 whereby alternate contact 146' of BB isclosed establishing a locking cir: cuit for itself so that BB remainsenergized until switch D is restored and alternate contact 130 of IPONinterrupted.

The connection from the calling line to an idle cord circuit E havingbeen completed, the master switch MS has its wipers advanced to the nextidle .pair of selector switches, this being brought about by theenergization of relays BB and RR. That is upon the closing of alternatecontacts 148, 136 of these relays, or in fact either one of thesecontacts, ground is connected to conductor 149 whereby a circuit foradvancing relay AB is established causing said relay to close itsalternate contact 150 whereby motor magnet MM advances the wipers 108,109 a single'step. then engaged lead to a busy pair of selectors LS, 'D,relay AR of course remains energized and magnet MM advances the wipersanother step. Should all of the remaining sets of contacts 110, 111, bebusy, upon the wipers 108, 109, advancing beyond the last contact of theset, over-run contact OR is closed establishing an energizing circuitfor the release magnet'RM which is therefore locked through itsalternate contact 151 and upon the energization of RM a retaining pawlis withdrawn allowing the wipers 108, 109 to be restored to normal byspring tension, in which position they are engaging the first set ofcontacts 110, 111. If this first set of contacts is idle, relay AR ofcourse does not energize and wipers remain inert, but if the first setof contacts are busy relay AR again energizes and. the magnet MMadvances the wipers until an idle set of contacts is reached. As

switches LS and D are restored so that the. $6

already pointed out, relays BB and BB remain energized until theirrespective conductor 149 is maintained grounded and finding the isclosed, establishing a locking.'-

If the set of contactsv the circuit for relay AS illumination thereof;Thus,

therefore the non-selectable until the connected pair of switches LS andD are again at normal.

The operator in response to the lighting of calling signal 11, connectsher operators telephone set (not shown) in bridge of the cord circuit Eand finding the substation is the desired one, she tests the jack Jthereof in the usual manner by touching the tip of the plug to'thesleeve of the-jack and line idle she inserts plug F to connect with thecalled line. Responsive to this connection a series circuit includingrelay SH lamp signal 12 and cut-ofi relay CO is established in a manneras described in connection with Fig.1, wherebysignal 12 is lighted anddue to the closing of contact 39 resistance 41 is connected in shuntwith signal 11 thereby efiacing said signal. Also upon energization ofSI-I its alternate contact 154 is closed connecting disconnect lamp DLin multiple with lamp 11 and resistance 41 but suflicient current doesnot flow through this lamp DL to cause its illumination until the.calling subscriber restores his receiver to deenergize rclay AS. Theoperator now depresses the proper ringing button whereby the bell of thecalled substation is operated and the automatic disconnection of theringing current isefiected upon response from the called substation in amanner as described in connection with Fig. 1. Upon response of thecalled subscriber at substation A calling supervisory relay ing theefl'acement of the signal 12 The two substations are now connected forconversation, the talking circuit being traced over the heavily markedconductors.

Disconnection in F 9. 3.

substation A causing relay CS to de'enerlamp 12 while at T interruptscausing its deenergization and the interruption of its contact 138. Thisinterruption of contact 138 disconnects lamp 11 and resistance 41 fromin shunt with disconnect lamp DL so that gize and again light signal thereplacing of the receiver said lamp DL is connected in series with i therelays GB, GL and CO causing the 12 being illuminated'the operator knowsthat the subscribers have replaced their receivers and removes plug Ffrom its jack, thereby interrupting the series circuit through relays SHand CO causing their deenergization. The restoration of SH by theinterruption of its alternate opens the and CO causing these threerelays to restore, the restoration of GB removing the busy potentlalfrom the associated group contact 154 circuit through relays GB, CL

lamps DL and nasa -lee contact 8 Upon restoration of GL the heavilymarked talking conductors are interrupted so that upon restoration ofthe wipers of the pair of switches LS and D any existing connectionsover which these for SM whereby the wipers are advanced to beautomatically released as described in connection with the switchmechanism. Upon switch LS returning to normal, alternate contact 121 ofPON is interrupted, thereby interrupting the circuit for SR whichrestores and switch LS is therefore at normal.

Now as to tne restoration of cord selector D its secondary relay SR isenergized upon said de'e'nergization of relay CD, the circuit beingtraced from battery to the winding of SE of alternate contact 133,normal contact 145, alternate contact 130 to ground at normal contact128. Relay SR therefore closes its alternate contact 131 establishing arelease circuit for SM so as to cause resto ration of switch 1)". Uponrestoration of the wipers to normal, alternate contact 130 of-PUN isinterrupted thereby opening the circuit for SR? and BB effecting thedeenergization of these relays whereby switch D is at normal. Relays R3and BB upon their deenergization disconnect ground from the conductor145 leading to the master switch MS whereby the associated pair ofselectors LS and D are available for use in establishing otherconnections. Upon the said deenergization of CO the line of substation Ais available for use in establishing other connections.

The system of Fig. 3 is also arranged to cause the automatic restorationof a pair of selectors LS and L should such a pair be started and failto connect a calling line and a cord circuit. 7

For instance should the receiver at substation A be removed andimmediately replaced, the associated line relay LE will be energizedsuiiiciently to ground the common starting conductor 212 and therebystart an idle pair of selectors LS and D but due to the fact that relayLE is only momentarily energized, ground is again connected to the groupcontact 107 associated therewith and individual test contact 104 so thatthis line which started a line selector is non-selectable. in such case,should no other line of the group be calling, all of the group contacts107 are in a grounded or non-selectable condition so that the primaryadjustment of switch LS is continued until the wipers have passed beyondthe last group of the switch and the primary over-run contact FUR isfiwclosed. Upon the switch reaching this point, and relay PR havingdeenergized due to the interruption of its maintaining circuit throughthe group wiper GT a circuit for secondary relay SR is closed fromgrounded normal contact 119 of PR over the previously described paththrough SE to battery whereby SR is energized causing an operation ofSM. Upon the first secondary step of switch LS, the initial enersogizing circuit for SR is interrupted at SON and test wiper T failing toconnect with a contact 10 1, relay SR immediately deenergizesinterrupting the circuit for SM and preventing any further secondarVance of the switch for the present. n the meantime assuming the cordselector D has selected an idle cord circuit E and its relay SR hasdeenergized, a circuit including closing relay GL and relay GB of cordcircuit so E is established from ground at FOR the windin oi": GL normalcontacts 140, 132, wiper and contact 5 conductor 139, the winding of GB,alternate contact 138 (which is closed due to the momentary enere5gization of A55 through normal contact 135 of SR lamp 11 to battery.Relay UL therefore energizes closes circuit for relays RR and BB in amanner as previously described whereby these relays are energized andlocked up as already pointed out. Upon said energization of GL itsnormal contact 134 is interrupted thereby interrupting the circuitthrough A8 which deenergizes due to the fact that there is no substituteenergizing circuit therefor over a calling line. Therefore relay AShaving failed to remain energized its contact 138 interrupts, againopening the circuit for GL which re stores to close ener izing circuitsthrou h are b a) (D lays SF and SE in manner as already described. Thatis relay SR is energized due to the closing of normal contact 1 13 of GLwhile SR is energized due to the sins ing of normal contact 145 of GLlays SR and SR therefore close release circuits through thecorresponding secondary magnets whereby switches LS and D have theirwipers advanced and then restored in a manner as previously described.Upon restoration of the wipers to normal relays SR BB BB and SR arereturned to normal and the switches LS and D are therefore available forestablishing other connections. Although the operation justdescribedcauses a momentary flash of signal 11 the operator can be instructed topay no attention to such signal or even should she connect her operatorstelephone circuit with the associated cord circuit she would 13 Said re-115 this over-run position,

receive no response and would know that no connection has beenestablished.

Another operation of the system of Fig.

3 which may sometimes occur, is Where a,.

call has been initiated and the calling line selected by a line selectorLS but the paired cord selector 1) fails to select a cord circuit Eeither because all the cordcircuits to which it has access are busy orbecause the primary adjustment of the switch D brings its wipers to agroup of cord circuits having a cord circuit of the group idle whenthe-group was selected but in which this idle cord circuit is seized byanother'selector D before the present selector D in its secondary travelreaches the terminals 5 6 7 thereof. k L

Assuming now that a call has been 1n1t1- ated at substation A and that,line L has been selected by a switch LS butthat the cord circuits towhich the paired selector D has access, are all busy. In this case theprimary adjustment of switch D is. continued until the wipers arestepped beyond contacts and switch the wipers reaching and the circuitfor PR being interrupted,this relay PR deener'gizes closing its normalcontact 128 and thereby closing the circuit for Slit which energizes andcauses magnet SM to advance the wipers a single secondary step andthereby interrupting contact. SON to open the initial energizing circuitof SR Wiper '1 having failed to engage a grounded contact 5 upon thifirst secondary step, relay the last groupof bank POR is closed. Upon SRrestores preventing any further secvondary ad ustment of the switchwipers for the present. i

Upon the switch I) reaching its prlmary over-run. position, contact 71of POR is closed whereby a circuit for over-run relay ORR is'established traced from battery through the winding thereof, alternatecontact 71 to ground at normal contact 136. Re-

lay ORR therefore energizes closing its alternate contact 7 2 andestablishing a series cirwinding of CO to ground. Said relays CO i socuit including CO and GL traced from battery through said contact 72alternate contact 7 3 conductor 162, normal contact 140, winding of CL,wiper W, contact, 105, the

CL are therefore energized, the energization of CO causing therestoration of LR and the interruption of the starting circuitoveryconducto'r 212 (providing no other line is calling at the time)while the energization of CL causes the energization of BB and BB asalready pointed out. Upon energization of BB and the interruption of its,normal contact 136, relay ORR restores thereby interrupting the seriescircuit through relays CL and CO so that these relays restore, therestoration of GL effecting he energization of the two secondary wherebythe switches LS and D are at normal and available for other use.

Although the first pair of selectors LS and D started failed to extendth calling line to an idle cord circuit E the present system is soarranged that a second pair of suchswitches are automatically started toattempt to effect such a connection. That is, as soon as relays RR RRare energized conductor 149 leading to master switch MS 1 is groundedthereby causing switch MS to advance its wipers to the next idle set ofcontacts. Therefore upon restoration of C0 of the calling line whenrelay 'OR R was denergized as pointed out above, the line circuit st llbeing closed at substation A line relay LE thereof is again energizedand a starting circuit including conductor 212 is again closed to startthe next set of idle selectors'LS and D Should this sec- 0nd pair ofswitches fail to establish a connection a third pair will be started andso on until one of such pairs of switches will connect the calling linewith an idle cord circuit E Another non-selecting operation of a pair ofstarted switches LS and D may occur in which the line selector will pickup the calling line but the paired cord selectors D will recelve itsprimary ad ustment to select a group of contacts having an idle set ofcontacts but before the wipers of this switch D in their secondaryadjustment, reach this set of contacts, some other switch D havingaccess to the connected cord circuit E seizes these contacts and rendersthem busy. In such case, assuming there is no other idle set of contactsin the group, the secondary adjustment of the wipers is continued untilthey have passed into a secondary over-run position. In this case switchSOR is closed connecting relay ORR in circuit to cause the restorationof the paired switches LS and D in a manner similar to that describedwhen the over-run switch POR is operated. Therefore switches LS and Dare restored to normal, and master switch MS advances to the next set ofidle contacts to start another pair of switches to connect the callingline with an idle cord circuit D Fig. 4. Fig. 4 illustrates a cordcircuit E adapted for use in place of cord circuitE, the circult of Fig.4 differing from cord circuit E 1n that'but single party line ringing isprovided and without any automatic control. The control of thesupervisory signals escapee of E is the same as that of E and I haveindicated the like parts by like reference characters except for the useof a diiferent suffix. The operation of IE will be apparent in view ofthe description of E and it is thought that no further reference to E isnecessary for an understanding thereof.

Although in illustrating my invention 1 have shown a plurality ofbatteries, it is to be understood that these batteries may be one andthe same in any exchange in accordance with common practice and althoughI have shown mechanical circuit interrupters on the operating magnets ofthe switches, I contemplate using either such interrupters or a sourceof alternating current. Furthermore, I am aware that many changes in thecircuit arrangements will readily suggest themselves and therefore I donot desire to be limited to the exact arrangements as shown but alm tocover all that which comes within the spirit and scope of the appendedclaims.

What I claim as new and desire to secure by United States Letters Patentis:'

1. An automatic two-dimension call distributing switch comprisingcontacts arranged in groups and coiiperating wipers, link ClICllltSextending from said contacts, multi le connections for said contactswhere y the link circuits may be rendered busy, a starting circuit forsaid switch, and means whereb if all of said circuits are busy when saiswitch is started said wipers are operated to test all of said groupsand automatically restore by both movements thereof. t

2. An automatic two-dimension call distributing switch comprisingcontacts arranged in groups and cooperating wipers, link circuitsextending from said contacts, other connections whereby the linkcircuits and contacts may be rendered busy, astarting circuit for saidswitch, means responsive to said starting circuit for causing a primaryadjustment of the wipers to'test all of said groups, and means efiectiveif all of said groups are busy for automatically causing a secondaryoperation and restoration of sald wipers to normal.

3. An automatic two-dimension call distributing switch comprisingcontacts arranged in groups and cotiperating wipers, a primary magnet, asecondary magnet, link circuits extending from said contacts, otherconnections rendering all of said contacts and link circuits busy, astarting circuit for said switch, means responsive to said startingcircuit for causing an automatic operation of said magnets whereby saidWipers test said contacts for an idle circuit and are thereafterautomatically restored to normal.

4. An automatic two-dimension call distributing switch comprisingcontacts arranged m groups and coiiperating wipers, a

primary magnet, a secondary magnet, link circuits extending from saidcontacts, other connections rendering all of said contacts and linkcircuits busy, a starting circuit for said switch, means responsive tosaid starting circuit for causing an automatic operation of the primarymagnet whereby said wipers test said contacts for a group having an idlecircuit, and means efiective when none such idle circuit is found forcausing an automatic operation of the secondary magnet to restore saidwipers to normal.

5. A telephone system comprising telephone lines, answering jackstherefor, operators link circuits including answering plugs, other linkscircuits, automatic switches responsive to the insertion of theanswering plugs into the jacks of calling lines for extending theoperators link circult of a plug to one of said other link cirlinkcircuits, a disconnect signal for said answering plug, and means foroperating said signal upon failure of said switch to find an idle linkcircuit.

7. A telephone system comprising telephone lines, answering jackstherefor, op-

erators link circuits includinganswering plugs, other operators linkcircuits including calling plugs, automatic switches equal in number tosaid first link circuits, and means responsive to the insertion of ananswering plug into the jack of a calling line for causing one of suchswitches to extend the circu1t of the operators link circuit of saidplug to an idle one of said calling link circuits.

8. A telephone system comprising a link circuit provided with ananswering plug, a second link circuit provided with a cal mg plug, andmeans responsive to the insertion of said answering plug into the jackof a calling line for automatically selecting and connecting said secondlink circuit to said first link circuit.

9. A telephone system comprising a plurality of A-operators" linkcircuits provided with answering plugs, a plurality of B-operators linkc1rcuits provided with calling plugs, and automatic means responsive tothe insertion of a calling plug of one of said first link circuits intothe jack of a calling line for connecting said link circuit to an idleone of said B-operators links circuits.

.10. A telephone system comprising an A- operators link circuit andB-operators link circuits, manual means for directly connecting saidA-operators link circuit to a calling line, and automatic trunkselecting means individual to the A operators link circuit responsive tosaid connection for automatically selecting and connecting saidA-operators link circuit to an idle one of said B-operators linkcircuits. 11. A telephone system comprising a plurality of link circuitsof one character and a plurality of link circuits of another character,manual means for interchangeably connecting said first link circuits andcalllng subscribers lines, automatic means individual to said first linkcircuit andresponsive to said connections for automaticallyinterchangeably selecting and connecting the said first link circuits toidle ones of said other link circuits, and supervisory signals for bothof said link circuits.

'12. A'telephone system comprising a link circuit, other link circuits,manual means for directly connectin said first link circuit to a callingsubscrlbers line, and auto matic means responsive to said connection forconnectin said link circuit to an idle one of said ot er link circuits.

13, A telephone-system comprising a calling subscribers line, aplug-ended link circuit, other link circuits, manual means for connectinsaid first link circuit to said calling su scribers line via saidplug,and automatic means responsive to said connection for connecting saidlink circuit to an idle one of said other link circuits.

- 14:. A telephone system including a calling and a called subscribersline, an operators plug-ended link circuit, a second link circuit, meansresponsive to the manual connection of said first link circuits to saidcalling line for automatically completing connection between said pairof link circuits, means for connecting the other of said link circuitsto said called ,line, and means responsive to the disconnection of saidlast link circuit from said called line for automatically interruptingconnection between said pair of link circuits.

15. A telephone system including a calling subscribers line and a calledsubscribers line, an opei'ators link circuit, a second operators linkcircuit, means responsive to the manual connection of said .first linkcircuit to said callingline for automatically connecting said first linkcircuit to said second link circuit, means for connecting said secondlink circuit to said called subscribers line, a supervisory signal forsaid first link circuit operable when said second link circuit isdisconnected from said called subscribers line, and operator-controlledmeans for then restoring said first link circuit.

16. A telephone system including a calling subscribers line and 2.called subscrib- I grou nection to said calling subscribers line,

other operators link circuits for connection to said called subscribersline, automatic means associated with said first link circuit andresponsive to the manual connection of said link circuit to said callingsubscribers line for connecting said link circuit to an idle one of saidother link circuits, means for connecting the selected link circuit tosaid called subscribers line, a supervisory signal for said first linkcircuit, and means for operating said supervisory'signal when saidselected link circuit is disconnected from said called line or if saidautomatic means does not find an idle link circuit.

17; A telephone system including a calling subscribers line, anautomatic switch, 'l1nk c1rcu1ts divided into groups and accessible tosaid automatic switch, manualmeans for connecting said switch to saidcalling subscribers line, and means responsive to said connection foroperating said switch to test said link circuits by groups until an idlegroup is found and for then testingtthe link circuits in the selectedgroup until an 'idle link circuit is found.

18. A telephone system comprising a calling subscribers line, anautomatic switch, link circuits divided into groups and accessible tosaid switch, a contact for each of said groups,'and means associatedwith each of link circuits for making its respect1ve contact test busy,and means re sponsive to the manual connection of said switch to saidcalling subscribers line for operating said switch to test said link circuits by groups. 7

19.; A telephone system comprising a callingsubscribers line, a linkcircuit, an automatic switch for said link circuit for extending. aconnection therefrom, means responsive to the connection of said linkcircuit to said calling subscribers line for operating said automaticswitch, independ-- ent means. for releasing said automatic switch, andmeans for preventing a reoperation of said automatic. switch until saidlink circuit'is disconnected from said line.

20. A telephone system including a calling subscribers'line and avcalledsubscribers line, a pair-of plug ended link circuits,

automatic means responsive to the manual connection of one of said linkcircuits tosaid calling subscribers line for establishing connectionbetween 'said link circuits,

means for connecting the other of said link circuits to said calledsubscribers line, and means responsive to the disconnection of said lastlink circuit from said called subscribers line to interrupt saidconnection between said llnk c1rcu1ts.

21. A telephone system including a callingsubscribers line and a calledsubscriber s hne, an operators hnk circuit, a second operators linkcircuit, manual means for directly connecting said link circuits to saldcalling and called subscribers lines respectively, automatic means forestablishing connection between said link circuits, a pair ofsupervisory signals for sald second link circuit under the control ofthe calling and called subscribers, and a disconnect signal for the saidfirst linkcircuit responsive to the disconnection of said other linkcircuit from said subscribers line.

22. A telephone system including a calling subscribers line and a calledsubscribers line, an operators plug-ended link circuit, a secondoperators plug-ended link circuit, means for connecting said linkcircuits to said calling and called subscribers lines, respectively,automatic means for establishing connection between said link circuits,:1

pair of supervisory signals for said second 2 link circuit under thecontrol of the and called subscribers, and a, disconnect signal for saidfirst link circuit responsive to the disconnection of said second linkcircuit from said subscribers line,

Signed by me at New Yorkin the county of New York and State of New Yorkin the presence of two witnesses. ALFRED H. DYSON, Witnesses: 7

W. F. HOFFMAN, G. E. MUELLER.

